Here the answer choices that accompany this question:
- Heat energy from the fire was radiated through the air to the candle
- Heat energy from the fire was conducted through the table to the candle
- Heat energy from the fire reached the candle by convection
- Heat energy from the fire was conducted through the air into the candle.
Answer:
- Heat energy from the fire was radiated through the air to the candle
Explanation:
Heat energy is transferred from hot sources to colder substances by any of three mechanisms: <em>conduction, convection, or radiation.</em>
<em>Conduction</em> only happens by direct contact of the objects because it relies of the transfer of kinetic energy by the vibration of the particles (atoms or molecules). Then this mechanism is not responsible of the melting of the candle which is to some distance of the fire. Hence, the second and the fourth choices are not correct.
<em>Convection</em> happens by the movement of fluids (liquids or gases): the liquids or gases when move carry on heat. The particles travel and carry on heat energy with them transfering heat from the hotter substance to the colder one. Fire does not move from the fireplace to the table where the candle is, hence the third option is also incorrect.
<em>Radiation</em> is the transfer of heat energy by electromagnetic waves. Electromagnetic waves do not require a physical medium to travel. Radiaton is a typical form of heat transfer from very hot objcets. Since fire is at a very high temperature, radiation heat transfer occurs to an important degree and is responsible for melting the candle. Hence, the first choice is correct.
